Using Pythagorean's Theorem of a^2+b^2=c^2, with a and b being two legs and c being the hypotenuse. You can find that the leg(15) squared is 225. The hypotenuse(17) squared is 289. 289-225=64 The square root of 64 is 8 So the missing leg of the triangle has a length of 8 units.
